\begin{tikzpicture}
    \tkzDefPoints{0/0/O}
    \tkzDefPoint(270:1.5){C}
    \tkzDefLine[perpendicular=through C,normed](O,C)  \tkzGetPoint{b}
    \tkzDefPointOnLine[pos=2.0](C,b)  \tkzGetPoint{B}
    \tkzDefPointOnLine[pos=2](B,C)  \tkzGetPoint{A}

    \tkzDrawCircle[thick](O,C)
    \tkzDrawPoint(O)
    \tkzDrawSegment[dashed](O,C)
    \tkzDrawSegments(O,A  O,B)
    \tkzDrawLine[add=.1 and .1](A,B)
    \tkzLabelPoints[above](O)
    \tkzLabelPoints[below](A,B,C)
\end{tikzpicture}

